procd: do not overwrite service data by default

Allows a running servie to manage its own data if untouched by the init script

Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry picked from commit 8c5826b140b6288b9270d232ecda0d540e380d4e)

package/base-files/files/etc/rc.common

@@ -100,10 +100,6 @@ service_triggers() {
 	return 0
 }
 
-service_data() {
-	return 0
-}
-
 service_running() {
 	local instance="${1:-*}"
 

package/system/procd/files/procd.sh

@@ -101,9 +101,11 @@ _procd_close_service() {
 	_procd_open_trigger
 	service_triggers
 	_procd_close_trigger
-	_procd_open_data
-	service_data
-	_procd_close_data
+	type service_data >/dev/null 2>&1 && {
+		_procd_open_data
+		service_data
+		_procd_close_data
+	}
 	_procd_ubus_call ${1:-set}
 }